Methods and apparatus for accessing and monitoring the gastrointestinal tract are described herein. One variation of a feeding tube system may generally comprise a gastric access device having a length, a controller in communication with the gastric access device, and one or more impedance or conductivity sensors positioned along the length and one or more temperature sensors positioned along the length. The controller may be configured to receive a first signal associated with the impedance or conductivity sensors and a second signal associated with respiration and determine whether a placement of the gastric access device is within a stomach of the subject.

In some embodiments, a body cavity shape of a subject is reconstructed based on intrabody measurements of voltages by an intrabody probe (for example, a catheter probe) moving within a plurality of differently-oriented electromagnetic fields crossing the body cavity. In some embodiments, the method uses distances between electrodes as a spatially calibrated ruler. Positions of measurements made with the intrabody probe in different positions are optionally related by using spatial coherence of the measured electromagnetic fields as a constraint. Optionally, reconstruction is performed without using a detailed reference (image or simulation) describing the body cavity shape. Optionally, reconstruction uses further information to refine and/or constrain the reconstruction; for example: images, simulations, additional electromagnetic fields, and/or measurements characteristic of body cavity landmarks. Optionally, reconstruction accounts for time-dependent cavity shape changes, for example, phasic changes (e.g., heartbeat and/or respiration), and/or changes in states such as subject hydration, edema, and/or heart rate.

Surgical visualization systems and related methods are disclosed herein, e.g., for providing visualization during surgical procedures. Systems and methods herein can be used in a wide range of surgical procedures, including spinal surgeries such as minimally-invasive fusion or discectomy procedures. Systems and methods herein can include various features for enhancing end user experience, improving clinical outcomes, or reducing the invasiveness of a surgery. Exemplary features can include access port integration, hands-free operation, active and/or passive lens cleaning, adjustable camera depth, and many others.

A medical device can be localized by providing at least three non-colinear localization elements (e.g., electrodes) thereon. Once placed in a non-ionizing localization field, three adjacent localization elements, at least one of which will typically be a spot electrode, may be selected, and the non-ionizing localization field may be used to measure their locations. A cylinder is defined to fit the measured locations of the selected localization elements. The cylinder is rotationally oriented using the measured location of a spot electrode. Location and rotational attitude information may be used to construct a three-dimensional representation of the medical device within the localization field. The electrodes may be provided on the medical device or on a sheath into which the medical device is inserted. The invention also provides systems and methods for identifying and calibrating deflection planes where the medical device and/or sheath are deflectable.

An illustrative insertion management system may be configured to monitor, during a lead insertion procedure in which an electrode lead having a plurality of electrodes is inserted into a cochlea of a recipient of a cochlear implant, impedance values for a subset of electrodes included in the plurality of electrodes, the subset of electrodes being less than a total number of the plurality of electrodes; detect, during the lead insertion procedure and based on the monitoring, an anomaly in the impedance values; and generate, during the lead insertion procedure and based on the anomaly, translocation log data indicating that a translocation event in which the electrode lead translocates from a first scala of the cochlea to a second scala of the cochlea is about to occur or has occurred during the lead insertion procedure.

A catheter adapted to determine a contact force, the catheter including a proximal segment, a distal segment, and an elastic segment extending from the proximal segment to the distal segment. The distal segment includes a plurality of tip electrodes including at least three radial electrodes disposed about a circumference of the distal segment. The radial electrodes are configured to output electrical signals indicative of a contact vector of the contact force. The elastic segment includes a force sensing device configured to output an electrical signal indicative of a magnitude of an axial component of the contact force, wherein the contact force is determined by scaling the magnitude of the axial component of the contact force by the contact vector.

A medical device can be localized by providing at least three non-colinear localization elements (e.g., electrodes) thereon. Once placed in a non-ionizing localization field, three adjacent localization elements, at least one of which will typically be a spot electrode, may be selected, and the non-ionizing localization field may be used to measure their locations. A cylinder is defined to fit the measured locations of the selected localization elements. The cylinder is rotationally oriented using the measured location of a spot electrode. Location and rotational attitude information may be used to construct a three-dimensional representation of the medical device within the localization field. The electrodes may be provided on the medical device or on a sheath into which the medical device is inserted. The invention also provides systems and methods for identifying and calibrating deflection planes where the medical device and/or sheath are deflectable.

A balloon catheter system has a balloon extending in an axial direction and surrounding a balloon interior. The balloon has an outer side facing away from the balloon interior. A catheter is connected to the balloon and extending in the axial direction, the catheter having a lumen in fluid communication with the balloon interior. First and second annular electrodes are disposed on the outer side, each extending in a circumferential direction of the balloon and being located opposite one another in the axial direction. The electrodes are configured to measure one of more of strain of the balloon in the circumferential direction, strain of the balloon in the radial direction, an impedance of tissue of a patient resting against the electrodes, and a redox potential of tissue of the patient contacting at least one of the electrodes.

Embodiments are directed to an implantable medical device comprising therapeutic stimulation circuitry for controlling delivery of a medical therapy to a patient, the therapeutic stimulation circuitry having at least one lead having electrodes for delivering the medical therapy, The implantable medical device further comprises measurement circuitry for determining characteristics of the at least one lead, a processor for controlling the IMD according to executable code, and memory for storing data and executable code, wherein the executable code comprises instructions for causing the processor to receive a plurality of voltage measurements associated with the electrodes, and calculate values for an impedance model of the electrode/tissue interface.

Disclosed herein is a system, apparatus and method directed to detecting malposition of a medical device within a vessel of a patient, such as an Azygos vein. The medical device can include a multi-core optical fiber including a plurality of core fibers, where each of the plurality of core fibers includes a plurality of sensors is configured to reflect a light signal based on received incident light, and change a characteristic of the reflected light signal for use in determining a physical state of the multi-core optical fiber. The system can include a console having non-transitory computer-readable medium storing logic that, when executed, causes operations of providing a broadband incident light signal to the multi-core optical fiber, receiving reflected light signals, processing the reflected light signals, and determining whether the medical device has entered the Azygos vein of the patient based on the reflected light signals.